Detergent containing sachets sealed with a water-sensitive coating composition are known from U.S. Pat. No. 2,760,942 (Hercules) and GB 1 583 082 (Unilever). GB 1 583 082 discloses a detergent sachet the seams of which are sealed with water soluble adhesives such as polysaccharides or polyvinyl alcohol.
Detergent containing sachets which are sealed with mechanically weak heat seals, which rupture when agitated, are described in EP 11 500B (Unilever).
GB 2 000 177B (Akzo) discloses detergent sachets sealed with material that disintegrates in the wash water at temperatures of from 40.degree. to 60.degree. C. The seal may consist of a mixture of polyethylene glycol which melts at 42.degree. C., together with a thermoplastic acrylic resin.
EP 143 476A (Akzo) discloses detergent sachets of heat-sealable material sealed with an anionic and/or water binding polymer, and a cationic polymeric adhesive, for example, polyethyleneimine.
Sachets intended to give sequential release are described, for example in European Patent Application No. 87 301905.3 (Unilever) filed on Mar. 5, 1987. Such sachets tend, however, to be of complicated construction.
Although containers provided with heat-sealed seams are known they do not provide the opening qualities required for many applications. Containers provided with liquid-labile seams are also known but they have a tendency to open prematurely during storage in the humid conditions found in many kitchens and bathrooms.